reasoninglayer 0.2.1

//! Proof-engine DTOs (term-store, rule-store, eval/builtin).

use std::collections::BTreeMap;

use serde::{Deserialize, Serialize};

/// Tagged value used throughout the term-store and rule-store surfaces.
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(tag = "type", rename_all = "snake_case")]
pub enum TermStoreValueDto {
    Integer { value: i64 },
    Real { value: f64 },
    String { value: String },
    Boolean { value: bool },
    Uninstantiated,
    Reference { term_id: String },
    List { items: Vec<TermStoreValueDto> },
}

// ─── Term-store ─────────────────────────────────────────────────────────────

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct CreateTermStoreRequest {
    pub tenant_id: String,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub owner_id: Option<String>,
}

#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct TermStoreSessionResponse {
    pub session_id: String,
    pub tenant_id: String,
    pub term_count: u64,
    pub variable_count: u64,
}

#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct CreateStoreTermRequest {
    pub sort_id: String,
    #[serde(default)]
    pub features: BTreeMap<String, TermStoreValueDto>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct CreateVariableRequest {
    pub sort_id: String,
}

#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct CreateTermResponse {
    pub term_id: String,
    pub is_variable: bool,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct BindVariableRequest {
    pub variable_id: String,
    pub target_id: String,
}

#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct BindVariableResponse {
    pub success: bool,
    pub variable_id: String,
    pub bound_to: String,
    pub trail_length: u64,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct UnifyTermsRequest {
    pub term1_id: String,
    pub term2_id: String,
}

#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct UnifyTermsResponse {
    pub success: bool,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub failure_reason: Option<String>,
    pub trail_length: u64,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub unified_term_id: Option<String>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct DereferenceRequest {
    pub term_id: String,
}

#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct DereferenceResponse {
    pub original_id: String,
    pub dereferenced_id: String,
    pub is_bound: bool,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SetFeatureRequest {
    pub term_id: String,
    pub feature_name: String,
    pub value: TermStoreValueDto,
}

#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct SetFeatureResponse {
    pub success: bool,
    pub term_id: String,
    pub feature_name: String,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct GetStoreTermRequest {
    pub term_id: String,
}

#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct GetStoreTermResponse {
    pub term_id: String,
    pub sort_id: String,
    #[serde(default)]
    pub features: BTreeMap<String, TermStoreValueDto>,
    pub is_variable: bool,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub bound_to: Option<String>,
}

#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct MarkTermStoreRequest {}

#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct MarkTermStoreResponse {
    pub marker_index: u64,
    pub trail_length: u64,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct BacktrackTermStoreRequest {
    pub marker_index: u64,
}

#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct BacktrackTermStoreResponse {
    pub success: bool,
    pub undone_entries: u64,
    pub current_trail_length: u64,
}

// ─── Rule-store ─────────────────────────────────────────────────────────────

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct CreateRuleStoreRequest {
    pub tenant_id: String,
}

#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct RuleStoreResponse {
    pub store_id: String,
    pub tenant_id: String,
    pub rule_count: u64,
}

/// Tagged constraint inside a rule clause.
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(tag = "type", rename_all = "snake_case")]
pub enum RuleConstraintDto {
    Sort {
        var_name: String,
        sort_id: String,
    },
    Feature {
        var_name: String,
        feature_name: String,
        value: TermStoreValueDto,
    },
    Equal {
        var1: String,
        var2: String,
    },
}

#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct RuleClauseDto {
    #[serde(default)]
    pub constraints: Vec<RuleConstraintDto>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct AssertRuleRequest {
    pub head: RuleClauseDto,
    #[serde(default)]
    pub body: Vec<RuleClauseDto>,
    #[serde(default)]
    pub assert_first: bool,
}

#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct AssertRuleResponse {
    pub rule_id: String,
    pub rule_count: u64,
}

#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct RetractRuleRequest {
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub rule_id: Option<String>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub pattern: Option<RuleClauseDto>,
    #[serde(default)]
    pub retract_all: bool,
}

#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct RetractRuleResponse {
    pub retracted_count: u64,
    #[serde(default)]
    pub retracted_ids: Vec<String>,
    pub remaining_count: u64,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct FindRulesRequest {
    pub pattern: RuleClauseDto,
}

#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct RuleDto {
    pub id: String,
    pub head: RuleClauseDto,
    #[serde(default)]
    pub body: Vec<RuleClauseDto>,
    pub is_fact: bool,
}

#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct FindRulesResponse {
    #[serde(default)]
    pub matching_rules: Vec<RuleDto>,
}

#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct MarkRuleStoreRequest {}

#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct MarkRuleStoreResponse {
    pub marker_index: u64,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct UndoRuleStoreRequest {
    pub marker_index: u64,
}

#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct UndoRuleStoreResponse {
    pub success: bool,
    pub rule_count: u64,
}

// ─── Eval / builtins ────────────────────────────────────────────────────────

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct EvalBuiltinRequest {
    pub function_name: String,
    pub arguments: Vec<TermStoreValueDto>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(tag = "status", rename_all = "snake_case")]
pub enum EvalBuiltinResponse {
    Success { result: TermStoreValueDto },
    SuccessUnit,
    Failure,
    Residuate { blocking_arg_index: u64 },
    Error { message: String },
}

#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct ListEvalFunctionsQuery {
    /// Optional category filter.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub category: Option<String>,
}

#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct EvalFunctionInfoDto {
    pub name: String,
    pub category: String,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub arity: Option<u64>,
    pub description: String,
}

#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct ListEvalFunctionsResponse {
    #[serde(default)]
    pub functions: Vec<EvalFunctionInfoDto>,
}